Not all communication needs to be encrypted but you should seriously consider using SSL encryption in these situations:

Encrypt any pages on your website that transmits financial information like credit cards

Encrypt any pages on your website that transmits other personal or sensitive information like social security numbers or medical information

Encrypt the login form on your website

Encrypt your email server so that you can send messages to it securely

Your customers won't trust your web site without an SSL certificate. According to Gartner Research, nearly 70 percent of online shoppers have terminated an online order because they did not "trust" the transaction. In those cases, 64 percent indicated that the presence of a trust mark would have likely prevented the termination. An SSL certificate and a site seal could stop people from abandoning your website and that means more money for you.